This is a competitive renewal application for T32 DK7260, entitled "Training Grant in Diabetes and Metabolism." Currently in its 30th year, this program has provided multi-disciplinary training in diabetes research for predoctoral students and postdoctoral fellows (MD and/or PhD) at the Research Division of the Joslin Diabetes Center in Boston. Its rationale is that: 1) diabetes is a devastating, and growing, world health problem;2) Joslin, given its rich history of diabetes research and its current breadth and excellence, is a unique environment for training the corps of researchers required to solve this problem;and 3) Joslin can already demonstrate an impressive research training record, recently enhanced by the institution of novel mentoring programs. The Program Director is Dr. Diane Mathis, who is supported by an Executive Committee. The postdoctoral training faculty consists of twenty-five investigators at the Joslin Diabetes Center;the predoctoral faculty is primarily the subset of nine individuals holding appointments in the Division of Medical Sciences at Harvard Medical School. The individual Preceptors provide a mentor-based research experience that ranges from the most basic through the preclinical to the clinical, exploiting approaches that span the computational, biophysical, biochemical, molecular biological, cellular biological and organismic. Areas of focus include insulin signaling, intermediary metabolism, vascular cell biology, islet cell physiology, obesity, immunology, epidemiology, genetics, mental health and, most recently, stem cell biology. Training is enhanced by Joslin's NIH-supported Diabetes and Endocrinology Research Center (DERC) and its strong ties with Harvard Medical School, both of which provide access to state-of-the-art technologies and a core of lectures/seminars by leading scientists from around the world. The program currently supports five postdoctoral fellows, three predoctoral students and two summer students. An important proposed evolution to the program is incorporation of the training activities of the Training Grant in Diabetes for Pediatric Endocrinologists (T32 DK63702), currently lead by Dr. Lori Laffel. The rationale is that: 1) an important need for Pediatric Endocrinologists remains unfulfilled;2) for the same combination of reasons as mentioned above, Joslin is also an outstanding environment for their education and development as clinician/scientists;and 3) such a consolidation stands to be more efficient and potentially very synergistic.